Digital to Analog with R2R Ladder Network

 Mixed-Circuits, Test-Measurement  No Responses »
Nov 082004
 
Digital to Analog with R2R Ladder Network

This is a R-2R Digital to Analog Converter, It converts a byte (8 bit) to a analog value. It has 256 levels including zero. This can be used to convert a byte sent from a microcontroller to a analog value like say 1.51 V. At full scale, when all 8 bits are high calibrate to give 2.55 V then ever bit increment is 0.01V, 10mV steps. If the eight bits inputs are from a counter you then will see a staircase waveform at output, each step being 10mV higher or lower depending on whether the counter is counting up or Read More …

 Posted by admin at 10:23 PM

LM311 Square Triangle Oscillator for PWM

 Mixed-Circuits  No Responses »
Nov 082004
 
LM311 Square Triangle Oscillator for PWM

LM311 is a comparator, It operates from single 5V supply or dual supplies,input current 150 nA, 50 V-50 mA output drive capability. TTL-CMOS compatible output. The Output is open collector so it can sink current but cannot source, a totem pole output can source and sink. In this Circuit R2 is the source or pull-up. The Output being high or low depends on which input is more dominant or positive. If + or non-inverting input is more positive than the – inverting input then output of LM311 is high impedance or high Z as output transistor of LM311 is turned Read More …

 Posted by admin at 1:01 AM  Tagged with:

Fixed frequency Variable duty cycle with 555

 555-Circuits, Mixed-Circuits  No Responses »
Oct 232004
 
Fixed frequency Variable duty cycle with 555

This circuit is based on a very old application note from exar, in this the frequency is fixed by IC1 and IC2 -P1 controls the duty cycle. you need to compute the R and C values to get what you need, LM555 data sheet. You have to study the circuit and do something more innovative perhaps, just copying is ok for learning but it will get you nowhere, so learn and then innovate, the eagle circuit is given below so you can learn by editing it, also design a PCB with it, and you can even make a PCB at Read More …

 Posted by admin at 12:28 PM  Tagged with:
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